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/*
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 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
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 *    may be used to endorse or promote products derived from this software
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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 */
package java.time;

import static java.time.LocalTime.SECONDS_PER_DAY;
import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.DAY_OF_YEAR;
import static java.time.temporal.ChronoField.EPOCH_DAY;
import static java.time.temporal.ChronoField.ERA;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.PROLEPTIC_MONTH;
import static java.time.temporal.ChronoField.YEAR;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.chrono.ChronoLocalDate;
import java.time.chrono.Era;
import java.time.chrono.IsoChronology;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.time.zone.ZoneOffsetTransition;
import java.time.zone.ZoneRules;
import java.util.Objects;

/**
 * A date without a time-zone in the ISO-8601 calendar system,
 * such as {@code 2007-12-03}.
 * <p>
 * {@code LocalDate} is an immutable date-time object that represents a date,
 * often viewed as year-month-day. Other date fields, such as day-of-year,
 * day-of-week and week-of-year, can also be accessed.
 * For example, the value "2nd October 2007" can be stored in a {@code LocalDate}.
 * <p>
 * This class does not store or represent a time or time-zone.
 * Instead, it is a description of the date, as used for birthdays.
 * It cannot represent an instant on the time-line without additional information
 * such as an offset or time-zone.
 * <p>
 * The ISO-8601 calendar system is the modern civil calendar system used today
 * in most of the world. It is equivalent to the proleptic Gregorian calendar
 * system, in which today's rules for leap years are applied for all time.
 * For most applications written today, the ISO-8601 rules are entirely suitable.
 * However, any application that makes use of historical dates, and requires them
 * to be accurate will find the ISO-8601 approach unsuitable.
 *
 * <p>
 * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
 * class; use of identity-sensitive operations (including reference equality
 * ({@code ==}), identity hash code, or synchronization) on instances of
 * {@code LocalDate} may have unpredictable results and should be avoided.
 * The {@code equals} method should be used for comparisons.
 *
 * @implSpec This class is immutable and thread-safe.
 * @since 1.8
 */
public final class LocalDate
    implements Temporal, TemporalAdjuster, ChronoLocalDate, Serializable {

  /**
   * The minimum supported {@code LocalDate}, '-999999999-01-01'.
   * This could be used by an application as a "far past" date.
   */
  public static final LocalDate MIN = LocalDate.of(Year.MIN_VALUE, 1, 1);
  /**
   * The maximum supported {@code LocalDate}, '+999999999-12-31'.
   * This could be used by an application as a "far future" date.
   */
  public static final LocalDate MAX = LocalDate.of(Year.MAX_VALUE, 12, 31);

  /**
   * Serialization version.
   */
  private static final long serialVersionUID = 2942565459149668126L;
  /**
   * The number of days in a 400 year cycle.
   */
  private static final int DAYS_PER_CYCLE = 146097;
  /**
   * The number of days from year zero to year 1970.
   * There are five 400 year cycles from year zero to 2000.
   * There are 7 leap years from 1970 to 2000.
   */
  static final long DAYS_0000_TO_1970 = (DAYS_PER_CYCLE * 5L) - (30L * 365L + 7L);

  /**
   * The year.
   */
  private final int year;
  /**
   * The month-of-year.
   */
  private final short month;
  /**
   * The day-of-month.
   */
  private final short day;

  //-----------------------------------------------------------------------

  /**
   * Obtains the current date from the system clock in the default time-zone.
   * <p>
   * This will query the {@link Clock#systemDefaultZone() system clock} in the default
   * time-zone to obtain the current date.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @return the current date using the system clock and default time-zone, not null
   */
  public static LocalDate now() {
    return now(Clock.systemDefaultZone());
  }

  /**
   * Obtains the current date from the system clock in the specified time-zone.
   * <p>
   * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
   * Specifying the time-zone avoids dependence on the default time-zone.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @param zone the zone ID to use, not null
   * @return the current date using the system clock, not null
   */
  public static LocalDate now(ZoneId zone) {
    return now(Clock.system(zone));
  }

  /**
   * Obtains the current date from the specified clock.
   * <p>
   * This will query the specified clock to obtain the current date - today.
   * Using this method allows the use of an alternate clock for testing.
   * The alternate clock may be introduced using {@link Clock dependency injection}.
   *
   * @param clock the clock to use, not null
   * @return the current date, not null
   */
  public static LocalDate now(Clock clock) {
    Objects.requireNonNull(clock, "clock");
    // inline to avoid creating object and Instant checks
    final Instant now = clock.instant();  // called once
    ZoneOffset offset = clock.getZone().getRules().getOffset(now);
    long epochSec = now.getEpochSecond() + offset.getTotalSeconds();  // overflow caught later
    long epochDay = Math.floorDiv(epochSec, SECONDS_PER_DAY);
    return LocalDate.ofEpochDay(epochDay);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code LocalDate} from a year, month and day.
   * <p>
   * This returns a {@code LocalDate} with the specified year, month and day-of-month.
   * The day must be valid for the year and month, otherwise an exception will be thrown.
   *
   * @param year the year to represent, from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, not null
   * @param dayOfMonth the day-of-month to represent, from 1 to 31
   * @return the local date, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-month is
   * invalid for the month-year
   */
  public static LocalDate of(int year, Month month, int dayOfMonth) {
    YEAR.checkValidValue(year);
    Objects.requireNonNull(month, "month");
    DAY_OF_MONTH.checkValidValue(dayOfMonth);
    return create(year, month.getValue(), dayOfMonth);
  }

  /**
   * Obtains an instance of {@code LocalDate} from a year, month and day.
   * <p>
   * This returns a {@code LocalDate} with the specified year, month and day-of-month.
   * The day must be valid for the year and month, otherwise an exception will be thrown.
   *
   * @param year the year to represent, from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, from 1 (January) to 12 (December)
   * @param dayOfMonth the day-of-month to represent, from 1 to 31
   * @return the local date, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-month is
   * invalid for the month-year
   */
  public static LocalDate of(int year, int month, int dayOfMonth) {
    YEAR.checkValidValue(year);
    MONTH_OF_YEAR.checkValidValue(month);
    DAY_OF_MONTH.checkValidValue(dayOfMonth);
    return create(year, month, dayOfMonth);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code LocalDate} from a year and day-of-year.
   * <p>
   * This returns a {@code LocalDate} with the specified year and day-of-year.
   * The day-of-year must be valid for the year, otherwise an exception will be thrown.
   *
   * @param year the year to represent, from MIN_YEAR to MAX_YEAR
   * @param dayOfYear the day-of-year to represent, from 1 to 366
   * @return the local date, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-year is
   * invalid for the year
   */
  public static LocalDate ofYearDay(int year, int dayOfYear) {
    YEAR.checkValidValue(year);
    DAY_OF_YEAR.checkValidValue(dayOfYear);
    boolean leap = IsoChronology.INSTANCE.isLeapYear(year);
    if (dayOfYear == 366 && leap == false) {
      throw new DateTimeException(
          "Invalid date 'DayOfYear 366' as '" + year + "' is not a leap year");
    }
    Month moy = Month.of((dayOfYear - 1) / 31 + 1);
    int monthEnd = moy.firstDayOfYear(leap) + moy.length(leap) - 1;
    if (dayOfYear > monthEnd) {
      moy = moy.plus(1);
    }
    int dom = dayOfYear - moy.firstDayOfYear(leap) + 1;
    return new LocalDate(year, moy.getValue(), dom);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code LocalDate} from the epoch day count.
   * <p>
   * This returns a {@code LocalDate} with the specified epoch-day.
   * The {@link ChronoField#EPOCH_DAY EPOCH_DAY} is a simple incrementing count
   * of days where day 0 is 1970-01-01. Negative numbers represent earlier days.
   *
   * @param epochDay the Epoch Day to convert, based on the epoch 1970-01-01
   * @return the local date, not null
   * @throws DateTimeException if the epoch day exceeds the supported date range
   */
  public static LocalDate ofEpochDay(long epochDay) {
    long zeroDay = epochDay + DAYS_0000_TO_1970;
    // find the march-based year
    zeroDay -= 60;  // adjust to 0000-03-01 so leap day is at end of four year cycle
    long adjust = 0;
    if (zeroDay < 0) {
      // adjust negative years to positive for calculation
      long adjustCycles = (zeroDay + 1) / DAYS_PER_CYCLE - 1;
      adjust = adjustCycles * 400;
      zeroDay += -adjustCycles * DAYS_PER_CYCLE;
    }
    long yearEst = (400 * zeroDay + 591) / DAYS_PER_CYCLE;
    long doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
    if (doyEst < 0) {
      // fix estimate
      yearEst--;
      doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
    }
    yearEst += adjust;  // reset any negative year
    int marchDoy0 = (int) doyEst;

    // convert march-based values back to january-based
    int marchMonth0 = (marchDoy0 * 5 + 2) / 153;
    int month = (marchMonth0 + 2) % 12 + 1;
    int dom = marchDoy0 - (marchMonth0 * 306 + 5) / 10 + 1;
    yearEst += marchMonth0 / 10;

    // check year now we are certain it is correct
    int year = YEAR.checkValidIntValue(yearEst);
    return new LocalDate(year, month, dom);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code LocalDate} from a temporal object.
   * <p>
   * This obtains a local date based on the specified temporal.
   * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
   * which this factory converts to an instance of {@code LocalDate}.
   * <p>
   * The conversion uses the {@link TemporalQueries#localDate()} query, which relies
   * on extracting the {@link ChronoField#EPOCH_DAY EPOCH_DAY} field.
   * <p>
   * This method matches the signature of the functional interface {@link TemporalQuery}
   * allowing it to be used as a query via method reference, {@code LocalDate::from}.
   *
   * @param temporal the temporal object to convert, not null
   * @return the local date, not null
   * @throws DateTimeException if unable to convert to a {@code LocalDate}
   */
  public static LocalDate from(TemporalAccessor temporal) {
    Objects.requireNonNull(temporal, "temporal");
    LocalDate date = temporal.query(TemporalQueries.localDate());
    if (date == null) {
      throw new DateTimeException("Unable to obtain LocalDate from TemporalAccessor: " +
          temporal + " of type " + temporal.getClass().getName());
    }
    return date;
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code LocalDate} from a text string such as {@code 2007-12-03}.
   * <p>
   * The string must represent a valid date and is parsed using
   * {@link java.time.format.DateTimeFormatter#ISO_LOCAL_DATE}.
   *
   * @param text the text to parse such as "2007-12-03", not null
   * @return the parsed local date, not null
   * @throws DateTimeParseException if the text cannot be parsed
   */
  public static LocalDate parse(CharSequence text) {
    return parse(text, DateTimeFormatter.ISO_LOCAL_DATE);
  }

  /**
   * Obtains an instance of {@code LocalDate} from a text string using a specific formatter.
   * <p>
   * The text is parsed using the formatter, returning a date.
   *
   * @param text the text to parse, not null
   * @param formatter the formatter to use, not null
   * @return the parsed local date, not null
   * @throws DateTimeParseException if the text cannot be parsed
   */
  public static LocalDate parse(CharSequence text, DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    return formatter.parse(text, LocalDate::from);
  }

  //-----------------------------------------------------------------------

  /**
   * Creates a local date from the year, month and day fields.
   *
   * @param year the year to represent, validated from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, from 1 to 12, validated
   * @param dayOfMonth the day-of-month to represent, validated from 1 to 31
   * @return the local date, not null
   * @throws DateTimeException if the day-of-month is invalid for the month-year
   */
  private static LocalDate create(int year, int month, int dayOfMonth) {
    if (dayOfMonth > 28) {
      int dom = 31;
      switch (month) {
        case 2:
          dom = (IsoChronology.INSTANCE.isLeapYear(year) ? 29 : 28);
          break;
        case 4:
        case 6:
        case 9:
        case 11:
          dom = 30;
          break;
      }
      if (dayOfMonth > dom) {
        if (dayOfMonth == 29) {
          throw new DateTimeException(
              "Invalid date 'February 29' as '" + year + "' is not a leap year");
        } else {
          throw new DateTimeException(
              "Invalid date '" + Month.of(month).name() + " " + dayOfMonth + "'");
        }
      }
    }
    return new LocalDate(year, month, dayOfMonth);
  }

  /**
   * Resolves the date, resolving days past the end of month.
   *
   * @param year the year to represent, validated from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, validated from 1 to 12
   * @param day the day-of-month to represent, validated from 1 to 31
   * @return the resolved date, not null
   */
  private static LocalDate resolvePreviousValid(int year, int month, int day) {
    switch (month) {
      case 2:
        day = Math.min(day, IsoChronology.INSTANCE.isLeapYear(year) ? 29 : 28);
        break;
      case 4:
      case 6:
      case 9:
      case 11:
        day = Math.min(day, 30);
        break;
    }
    return new LocalDate(year, month, day);
  }

  /**
   * Constructor, previously validated.
   *
   * @param year the year to represent, from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, not null
   * @param dayOfMonth the day-of-month to represent, valid for year-month, from 1 to 31
   */
  private LocalDate(int year, int month, int dayOfMonth) {
    this.year = year;
    this.month = (short) month;
    this.day = (short) dayOfMonth;
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the specified field is supported.
   * <p>
   * This checks if this date can be queried for the specified field.
   * If false, then calling the {@link #range(TemporalField) range},
   * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
   * methods will throw an exception.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The supported fields are:
   * <ul>
   * <li>{@code DAY_OF_WEEK}
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
   * <li>{@code DAY_OF_MONTH}
   * <li>{@code DAY_OF_YEAR}
   * <li>{@code EPOCH_DAY}
   * <li>{@code ALIGNED_WEEK_OF_MONTH}
   * <li>{@code ALIGNED_WEEK_OF_YEAR}
   * <li>{@code MONTH_OF_YEAR}
   * <li>{@code PROLEPTIC_MONTH}
   * <li>{@code YEAR_OF_ERA}
   * <li>{@code YEAR}
   * <li>{@code ERA}
   * </ul>
   * All other {@code ChronoField} instances will return false.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the field is supported is determined by the field.
   *
   * @param field the field to check, null returns false
   * @return true if the field is supported on this date, false if not
   */
  @Override  // override for Javadoc
  public boolean isSupported(TemporalField field) {
    return ChronoLocalDate.super.isSupported(field);
  }

  /**
   * Checks if the specified unit is supported.
   * <p>
   * This checks if the specified unit can be added to, or subtracted from, this date.
   * If false, then calling the {@link #plus(long, TemporalUnit)} and
   * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
   * <p>
   * If the unit is a {@link ChronoUnit} then the query is implemented here.
   * The supported units are:
   * <ul>
   * <li>{@code DAYS}
   * <li>{@code WEEKS}
   * <li>{@code MONTHS}
   * <li>{@code YEARS}
   * <li>{@code DECADES}
   * <li>{@code CENTURIES}
   * <li>{@code MILLENNIA}
   * <li>{@code ERAS}
   * </ul>
   * All other {@code ChronoUnit} instances will return false.
   * <p>
   * If the unit is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
   * passing {@code this} as the argument.
   * Whether the unit is supported is determined by the unit.
   *
   * @param unit the unit to check, null returns false
   * @return true if the unit can be added/subtracted, false if not
   */
  @Override  // override for Javadoc
  public boolean isSupported(TemporalUnit unit) {
    return ChronoLocalDate.super.isSupported(unit);
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the range of valid values for the specified field.
   * <p>
   * The range object expresses the minimum and maximum valid values for a field.
   * This date is used to enhance the accuracy of the returned range.
   * If it is not possible to return the range, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return
   * appropriate range instances.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the range can be obtained is determined by the field.
   *
   * @param field the field to query the range for, not null
   * @return the range of valid values for the field, not null
   * @throws DateTimeException if the range for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   */
  @Override
  public ValueRange range(TemporalField field) {
    if (field instanceof ChronoField) {
      ChronoField f = (ChronoField) field;
      if (f.isDateBased()) {
        switch (f) {
          case DAY_OF_MONTH:
            return ValueRange.of(1, lengthOfMonth());
          case DAY_OF_YEAR:
            return ValueRange.of(1, lengthOfYear());
          case ALIGNED_WEEK_OF_MONTH:
            return ValueRange.of(1, getMonth() == Month.FEBRUARY && isLeapYear() == false ? 4 : 5);
          case YEAR_OF_ERA:
            return (getYear() <= 0 ? ValueRange.of(1, Year.MAX_VALUE + 1)
                : ValueRange.of(1, Year.MAX_VALUE));
        }
        return field.range();
      }
      throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
    }
    return field.rangeRefinedBy(this);
  }

  /**
   * Gets the value of the specified field from this date as an {@code int}.
   * <p>
   * This queries this date for the value of the specified field.
   * The returned value will always be within the valid range of values for the field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return valid
   * values based on this date, except {@code EPOCH_DAY} and {@code PROLEPTIC_MONTH}
   * which are too large to fit in an {@code int} and throw a {@code DateTimeException}.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field
   * @throws DateTimeException if a value for the field cannot be obtained or the value is outside
   * the range of valid values for the field
   * @throws UnsupportedTemporalTypeException if the field is not supported or the range of values
   * exceeds an {@code int}
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override  // override for Javadoc and performance
  public int get(TemporalField field) {
    if (field instanceof ChronoField) {
      return get0(field);
    }
    return ChronoLocalDate.super.get(field);
  }

  /**
   * Gets the value of the specified field from this date as a {@code long}.
   * <p>
   * This queries this date for the value of the specified field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return valid
   * values based on this date.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field
   * @throws DateTimeException if a value for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public long getLong(TemporalField field) {
    if (field instanceof ChronoField) {
      if (field == EPOCH_DAY) {
        return toEpochDay();
      }
      if (field == PROLEPTIC_MONTH) {
        return getProlepticMonth();
      }
      return get0(field);
    }
    return field.getFrom(this);
  }

  private int get0(TemporalField field) {
    switch ((ChronoField) field) {
      case DAY_OF_WEEK:
        return getDayOfWeek().getValue();
      case ALIGNED_DAY_OF_WEEK_IN_MONTH:
        return ((day - 1) % 7) + 1;
      case ALIGNED_DAY_OF_WEEK_IN_YEAR:
        return ((getDayOfYear() - 1) % 7) + 1;
      case DAY_OF_MONTH:
        return day;
      case DAY_OF_YEAR:
        return getDayOfYear();
      case EPOCH_DAY:
        throw new UnsupportedTemporalTypeException(
            "Invalid field 'EpochDay' for get() method, use getLong() instead");
      case ALIGNED_WEEK_OF_MONTH:
        return ((day - 1) / 7) + 1;
      case ALIGNED_WEEK_OF_YEAR:
        return ((getDayOfYear() - 1) / 7) + 1;
      case MONTH_OF_YEAR:
        return month;
      case PROLEPTIC_MONTH:
        throw new UnsupportedTemporalTypeException(
            "Invalid field 'ProlepticMonth' for get() method, use getLong() instead");
      case YEAR_OF_ERA:
        return (year >= 1 ? year : 1 - year);
      case YEAR:
        return year;
      case ERA:
        return (year >= 1 ? 1 : 0);
    }
    throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
  }

  private long getProlepticMonth() {
    return (year * 12L + month - 1);
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the chronology of this date, which is the ISO calendar system.
   * <p>
   * The {@code Chronology} represents the calendar system in use.
   * The ISO-8601 calendar system is the modern civil calendar system used today
   * in most of the world. It is equivalent to the proleptic Gregorian calendar
   * system, in which today's rules for leap years are applied for all time.
   *
   * @return the ISO chronology, not null
   */
  @Override
  public IsoChronology getChronology() {
    return IsoChronology.INSTANCE;
  }

  /**
   * Gets the era applicable at this date.
   * <p>
   * The official ISO-8601 standard does not define eras, however {@code IsoChronology} does.
   * It defines two eras, 'CE' from year one onwards and 'BCE' from year zero backwards.
   * Since dates before the Julian-Gregorian cutover are not in line with history,
   * the cutover between 'BCE' and 'CE' is also not aligned with the commonly used
   * eras, often referred to using 'BC' and 'AD'.
   * <p>
   * Users of this class should typically ignore this method as it exists primarily
   * to fulfill the {@link ChronoLocalDate} contract where it is necessary to support
   * the Japanese calendar system.
   * <p>
   * The returned era will be a singleton capable of being compared with the constants
   * in {@link IsoChronology} using the {@code ==} operator.
   *
   * @return the {@code IsoChronology} era constant applicable at this date, not null
   */
  @Override // override for Javadoc
  public Era getEra() {
    return ChronoLocalDate.super.getEra();
  }

  /**
   * Gets the year field.
   * <p>
   * This method returns the primitive {@code int} value for the year.
   * <p>
   * The year returned by this method is proleptic as per {@code get(YEAR)}.
   * To obtain the year-of-era, use {@code get(YEAR_OF_ERA)}.
   *
   * @return the year, from MIN_YEAR to MAX_YEAR
   */
  public int getYear() {
    return year;
  }

  /**
   * Gets the month-of-year field from 1 to 12.
   * <p>
   * This method returns the month as an {@code int} from 1 to 12.
   * Application code is frequently clearer if the enum {@link Month}
   * is used by calling {@link #getMonth()}.
   *
   * @return the month-of-year, from 1 to 12
   * @see #getMonth()
   */
  public int getMonthValue() {
    return month;
  }

  /**
   * Gets the month-of-year field using the {@code Month} enum.
   * <p>
   * This method returns the enum {@link Month} for the month.
   * This avoids confusion as to what {@code int} values mean.
   * If you need access to the primitive {@code int} value then the enum
   * provides the {@link Month#getValue() int value}.
   *
   * @return the month-of-year, not null
   * @see #getMonthValue()
   */
  public Month getMonth() {
    return Month.of(month);
  }

  /**
   * Gets the day-of-month field.
   * <p>
   * This method returns the primitive {@code int} value for the day-of-month.
   *
   * @return the day-of-month, from 1 to 31
   */
  public int getDayOfMonth() {
    return day;
  }

  /**
   * Gets the day-of-year field.
   * <p>
   * This method returns the primitive {@code int} value for the day-of-year.
   *
   * @return the day-of-year, from 1 to 365, or 366 in a leap year
   */
  public int getDayOfYear() {
    return getMonth().firstDayOfYear(isLeapYear()) + day - 1;
  }

  /**
   * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
   * <p>
   * This method returns the enum {@link DayOfWeek} for the day-of-week.
   * This avoids confusion as to what {@code int} values mean.
   * If you need access to the primitive {@code int} value then the enum
   * provides the {@link DayOfWeek#getValue() int value}.
   * <p>
   * Additional information can be obtained from the {@code DayOfWeek}.
   * This includes textual names of the values.
   *
   * @return the day-of-week, not null
   */
  public DayOfWeek getDayOfWeek() {
    int dow0 = (int) Math.floorMod(toEpochDay() + 3, 7);
    return DayOfWeek.of(dow0 + 1);
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the year is a leap year, according to the ISO proleptic
   * calendar system rules.
   * <p>
   * This method applies the current rules for leap years across the whole time-line.
   * In general, a year is a leap year if it is divisible by four without
   * remainder. However, years divisible by 100, are not leap years, with
   * the exception of years divisible by 400 which are.
   * <p>
   * For example, 1904 is a leap year it is divisible by 4.
   * 1900 was not a leap year as it is divisible by 100, however 2000 was a
   * leap year as it is divisible by 400.
   * <p>
   * The calculation is proleptic - applying the same rules into the far future and far past.
   * This is historically inaccurate, but is correct for the ISO-8601 standard.
   *
   * @return true if the year is leap, false otherwise
   */
  @Override // override for Javadoc and performance
  public boolean isLeapYear() {
    return IsoChronology.INSTANCE.isLeapYear(year);
  }

  /**
   * Returns the length of the month represented by this date.
   * <p>
   * This returns the length of the month in days.
   * For example, a date in January would return 31.
   *
   * @return the length of the month in days
   */
  @Override
  public int lengthOfMonth() {
    switch (month) {
      case 2:
        return (isLeapYear() ? 29 : 28);
      case 4:
      case 6:
      case 9:
      case 11:
        return 30;
      default:
        return 31;
    }
  }

  /**
   * Returns the length of the year represented by this date.
   * <p>
   * This returns the length of the year in days, either 365 or 366.
   *
   * @return 366 if the year is leap, 365 otherwise
   */
  @Override // override for Javadoc and performance
  public int lengthOfYear() {
    return (isLeapYear() ? 366 : 365);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns an adjusted copy of this date.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the date adjusted.
   * The adjustment takes place using the specified adjuster strategy object.
   * Read the documentation of the adjuster to understand what adjustment will be made.
   * <p>
   * A simple adjuster might simply set the one of the fields, such as the year field.
   * A more complex adjuster might set the date to the last day of the month.
   * <p>
   * A selection of common adjustments is provided in
   * {@link java.time.temporal.TemporalAdjusters TemporalAdjusters}.
   * These include finding the "last day of the month" and "next Wednesday".
   * Key date-time classes also implement the {@code TemporalAdjuster} interface,
   * such as {@link Month} and {@link java.time.MonthDay MonthDay}.
   * The adjuster is responsible for handling special cases, such as the varying
   * lengths of month and leap years.
   * <p>
   * For example this code returns a date on the last day of July:
   * <pre>
   *  import static java.time.Month.*;
   *  import static java.time.temporal.TemporalAdjusters.*;
   *
   *  result = localDate.with(JULY).with(lastDayOfMonth());
   * </pre>
   * <p>
   * The result of this method is obtained by invoking the
   * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
   * specified adjuster passing {@code this} as the argument.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param adjuster the adjuster to use, not null
   * @return a {@code LocalDate} based on {@code this} with the adjustment made, not null
   * @throws DateTimeException if the adjustment cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate with(TemporalAdjuster adjuster) {
    // optimizations
    if (adjuster instanceof LocalDate) {
      return (LocalDate) adjuster;
    }
    return (LocalDate) adjuster.adjustInto(this);
  }

  /**
   * Returns a copy of this date with the specified field set to a new value.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the value
   * for the specified field changed.
   * This can be used to change any supported field, such as the year, month or day-of-month.
   * If it is not possible to set the value, because the field is not supported or for
   * some other reason, an exception is thrown.
   * <p>
   * In some cases, changing the specified field can cause the resulting date to become invalid,
   * such as changing the month from 31st January to February would make the day-of-month invalid.
   * In cases like this, the field is responsible for resolving the date. Typically it will choose
   * the previous valid date, which would be the last valid day of February in this example.
   * <p>
   * If the field is a {@link ChronoField} then the adjustment is implemented here.
   * The supported fields behave as follows:
   * <ul>
   * <li>{@code DAY_OF_WEEK} -
   * Returns a {@code LocalDate} with the specified day-of-week.
   * The date is adjusted up to 6 days forward or backward within the boundary
   * of a Monday to Sunday week.
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
   * Returns a {@code LocalDate} with the specified aligned-day-of-week.
   * The date is adjusted to the specified month-based aligned-day-of-week.
   * Aligned weeks are counted such that the first week of a given month starts
   * on the first day of that month.
   * This may cause the date to be moved up to 6 days into the following month.
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
   * Returns a {@code LocalDate} with the specified aligned-day-of-week.
   * The date is adjusted to the specified year-based aligned-day-of-week.
   * Aligned weeks are counted such that the first week of a given year starts
   * on the first day of that year.
   * This may cause the date to be moved up to 6 days into the following year.
   * <li>{@code DAY_OF_MONTH} -
   * Returns a {@code LocalDate} with the specified day-of-month.
   * The month and year will be unchanged. If the day-of-month is invalid for the
   * year and month, then a {@code DateTimeException} is thrown.
   * <li>{@code DAY_OF_YEAR} -
   * Returns a {@code LocalDate} with the specified day-of-year.
   * The year will be unchanged. If the day-of-year is invalid for the
   * year, then a {@code DateTimeException} is thrown.
   * <li>{@code EPOCH_DAY} -
   * Returns a {@code LocalDate} with the specified epoch-day.
   * This completely replaces the date and is equivalent to {@link #ofEpochDay(long)}.
   * <li>{@code ALIGNED_WEEK_OF_MONTH} -
   * Returns a {@code LocalDate} with the specified aligned-week-of-month.
   * Aligned weeks are counted such that the first week of a given month starts
   * on the first day of that month.
   * This adjustment moves the date in whole week chunks to match the specified week.
   * The result will have the same day-of-week as this date.
   * This may cause the date to be moved into the following month.
   * <li>{@code ALIGNED_WEEK_OF_YEAR} -
   * Returns a {@code LocalDate} with the specified aligned-week-of-year.
   * Aligned weeks are counted such that the first week of a given year starts
   * on the first day of that year.
   * This adjustment moves the date in whole week chunks to match the specified week.
   * The result will have the same day-of-week as this date.
   * This may cause the date to be moved into the following year.
   * <li>{@code MONTH_OF_YEAR} -
   * Returns a {@code LocalDate} with the specified month-of-year.
   * The year will be unchanged. The day-of-month will also be unchanged,
   * unless it would be invalid for the new month and year. In that case, the
   * day-of-month is adjusted to the maximum valid value for the new month and year.
   * <li>{@code PROLEPTIC_MONTH} -
   * Returns a {@code LocalDate} with the specified proleptic-month.
   * The day-of-month will be unchanged, unless it would be invalid for the new month
   * and year. In that case, the day-of-month is adjusted to the maximum valid value
   * for the new month and year.
   * <li>{@code YEAR_OF_ERA} -
   * Returns a {@code LocalDate} with the specified year-of-era.
   * The era and month will be unchanged. The day-of-month will also be unchanged,
   * unless it would be invalid for the new month and year. In that case, the
   * day-of-month is adjusted to the maximum valid value for the new month and year.
   * <li>{@code YEAR} -
   * Returns a {@code LocalDate} with the specified year.
   * The month will be unchanged. The day-of-month will also be unchanged,
   * unless it would be invalid for the new month and year. In that case, the
   * day-of-month is adjusted to the maximum valid value for the new month and year.
   * <li>{@code ERA} -
   * Returns a {@code LocalDate} with the specified era.
   * The year-of-era and month will be unchanged. The day-of-month will also be unchanged,
   * unless it would be invalid for the new month and year. In that case, the
   * day-of-month is adjusted to the maximum valid value for the new month and year.
   * </ul>
   * <p>
   * In all cases, if the new value is outside the valid range of values for the field
   * then a {@code DateTimeException} will be thrown.
   * <p>
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
   * passing {@code this} as the argument. In this case, the field determines
   * whether and how to adjust the instant.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param field the field to set in the result, not null
   * @param newValue the new value of the field in the result
   * @return a {@code LocalDate} based on {@code this} with the specified field set, not null
   * @throws DateTimeException if the field cannot be set
   * @throws UnsupportedTemporalTypeException if the field is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate with(TemporalField field, long newValue) {
    if (field instanceof ChronoField) {
      ChronoField f = (ChronoField) field;
      f.checkValidValue(newValue);
      switch (f) {
        case DAY_OF_WEEK:
          return plusDays(newValue - getDayOfWeek().getValue());
        case ALIGNED_DAY_OF_WEEK_IN_MONTH:
          return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_MONTH));
        case ALIGNED_DAY_OF_WEEK_IN_YEAR:
          return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_YEAR));
        case DAY_OF_MONTH:
          return withDayOfMonth((int) newValue);
        case DAY_OF_YEAR:
          return withDayOfYear((int) newValue);
        case EPOCH_DAY:
          return LocalDate.ofEpochDay(newValue);
        case ALIGNED_WEEK_OF_MONTH:
          return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_MONTH));
        case ALIGNED_WEEK_OF_YEAR:
          return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_YEAR));
        case MONTH_OF_YEAR:
          return withMonth((int) newValue);
        case PROLEPTIC_MONTH:
          return plusMonths(newValue - getProlepticMonth());
        case YEAR_OF_ERA:
          return withYear((int) (year >= 1 ? newValue : 1 - newValue));
        case YEAR:
          return withYear((int) newValue);
        case ERA:
          return (getLong(ERA) == newValue ? this : withYear(1 - year));
      }
      throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
    }
    return field.adjustInto(this, newValue);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code LocalDate} with the year altered. <p> If the day-of-month is
   * invalid for the year, it will be changed to the last valid day of the month. <p> This instance
   * is immutable and unaffected by this method call.
   *
   * @param year the year to set in the result, from MIN_YEAR to MAX_YEAR
   * @return a {@code LocalDate} based on this date with the requested year, not null
   * @throws DateTimeException if the year value is invalid
   */
  public LocalDate withYear(int year) {
    if (this.year == year) {
      return this;
    }
    YEAR.checkValidValue(year);
    return resolvePreviousValid(year, month, day);
  }

  /**
   * Returns a copy of this {@code LocalDate} with the month-of-year altered. <p> If the
   * day-of-month is invalid for the year, it will be changed to the last valid day of the month.
   * <p> This instance is immutable and unaffected by this method call.
   *
   * @param month the month-of-year to set in the result, from 1 (January) to 12 (December)
   * @return a {@code LocalDate} based on this date with the requested month, not null
   * @throws DateTimeException if the month-of-year value is invalid
   */
  public LocalDate withMonth(int month) {
    if (this.month == month) {
      return this;
    }
    MONTH_OF_YEAR.checkValidValue(month);
    return resolvePreviousValid(year, month, day);
  }

  /**
   * Returns a copy of this {@code LocalDate} with the day-of-month altered.
   * <p>
   * If the resulting date is invalid, an exception is thrown.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param dayOfMonth the day-of-month to set in the result, from 1 to 28-31
   * @return a {@code LocalDate} based on this date with the requested day, not null
   * @throws DateTimeException if the day-of-month value is invalid, or if the day-of-month is
   * invalid for the month-year
   */
  public LocalDate withDayOfMonth(int dayOfMonth) {
    if (this.day == dayOfMonth) {
      return this;
    }
    return of(year, month, dayOfMonth);
  }

  /**
   * Returns a copy of this {@code LocalDate} with the day-of-year altered.
   * <p>
   * If the resulting date is invalid, an exception is thrown.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param dayOfYear the day-of-year to set in the result, from 1 to 365-366
   * @return a {@code LocalDate} based on this date with the requested day, not null
   * @throws DateTimeException if the day-of-year value is invalid, or if the day-of-year is invalid
   * for the year
   */
  public LocalDate withDayOfYear(int dayOfYear) {
    if (this.getDayOfYear() == dayOfYear) {
      return this;
    }
    return ofYearDay(year, dayOfYear);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this date with the specified amount added.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the specified amount added.
   * The amount is typically {@link Period} but may be any other type implementing
   * the {@link TemporalAmount} interface.
   * <p>
   * The calculation is delegated to the amount object by calling
   * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
   * to implement the addition in any way it wishes, however it typically
   * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
   * of the amount implementation to determine if it can be successfully added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToAdd the amount to add, not null
   * @return a {@code LocalDate} based on this date with the addition made, not null
   * @throws DateTimeException if the addition cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate plus(TemporalAmount amountToAdd) {
    if (amountToAdd instanceof Period) {
      Period periodToAdd = (Period) amountToAdd;
      return plusMonths(periodToAdd.toTotalMonths()).plusDays(periodToAdd.getDays());
    }
    Objects.requireNonNull(amountToAdd, "amountToAdd");
    return (LocalDate) amountToAdd.addTo(this);
  }

  /**
   * Returns a copy of this date with the specified amount added.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the amount
   * in terms of the unit added. If it is not possible to add the amount, because the
   * unit is not supported or for some other reason, an exception is thrown.
   * <p>
   * In some cases, adding the amount can cause the resulting date to become invalid.
   * For example, adding one month to 31st January would result in 31st February.
   * In cases like this, the unit is responsible for resolving the date.
   * Typically it will choose the previous valid date, which would be the last valid
   * day of February in this example.
   * <p>
   * If the field is a {@link ChronoUnit} then the addition is implemented here.
   * The supported fields behave as follows:
   * <ul>
   * <li>{@code DAYS} -
   * Returns a {@code LocalDate} with the specified number of days added.
   * This is equivalent to {@link #plusDays(long)}.
   * <li>{@code WEEKS} -
   * Returns a {@code LocalDate} with the specified number of weeks added.
   * This is equivalent to {@link #plusWeeks(long)} and uses a 7 day week.
   * <li>{@code MONTHS} -
   * Returns a {@code LocalDate} with the specified number of months added.
   * This is equivalent to {@link #plusMonths(long)}.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * <li>{@code YEARS} -
   * Returns a {@code LocalDate} with the specified number of years added.
   * This is equivalent to {@link #plusYears(long)}.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * <li>{@code DECADES} -
   * Returns a {@code LocalDate} with the specified number of decades added.
   * This is equivalent to calling {@link #plusYears(long)} with the amount
   * multiplied by 10.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * <li>{@code CENTURIES} -
   * Returns a {@code LocalDate} with the specified number of centuries added.
   * This is equivalent to calling {@link #plusYears(long)} with the amount
   * multiplied by 100.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * <li>{@code MILLENNIA} -
   * Returns a {@code LocalDate} with the specified number of millennia added.
   * This is equivalent to calling {@link #plusYears(long)} with the amount
   * multiplied by 1,000.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * <li>{@code ERAS} -
   * Returns a {@code LocalDate} with the specified number of eras added.
   * Only two eras are supported so the amount must be one, zero or minus one.
   * If the amount is non-zero then the year is changed such that the year-of-era
   * is unchanged.
   * The day-of-month will be unchanged unless it would be invalid for the new
   * month and year. In that case, the day-of-month is adjusted to the maximum
   * valid value for the new month and year.
   * </ul>
   * <p>
   * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
   * passing {@code this} as the argument. In this case, the unit determines
   * whether and how to perform the addition.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToAdd the amount of the unit to add to the result, may be negative
   * @param unit the unit of the amount to add, not null
   * @return a {@code LocalDate} based on this date with the specified amount added, not null
   * @throws DateTimeException if the addition cannot be made
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate plus(long amountToAdd, TemporalUnit unit) {
    if (unit instanceof ChronoUnit) {
      ChronoUnit f = (ChronoUnit) unit;
      switch (f) {
        case DAYS:
          return plusDays(amountToAdd);
        case WEEKS:
          return plusWeeks(amountToAdd);
        case MONTHS:
          return plusMonths(amountToAdd);
        case YEARS:
          return plusYears(amountToAdd);
        case DECADES:
          return plusYears(Math.multiplyExact(amountToAdd, 10));
        case CENTURIES:
          return plusYears(Math.multiplyExact(amountToAdd, 100));
        case MILLENNIA:
          return plusYears(Math.multiplyExact(amountToAdd, 1000));
        case ERAS:
          return with(ERA, Math.addExact(getLong(ERA), amountToAdd));
      }
      throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
    }
    return unit.addTo(this, amountToAdd);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of years added.
   * <p>
   * This method adds the specified amount to the years field in three steps:
   * <ol>
   * <li>Add the input years to the year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2008-02-29 (leap year) plus one year would result in the
   * invalid date 2009-02-29 (standard year). Instead of returning an invalid
   * result, the last valid day of the month, 2009-02-28, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param yearsToAdd the years to add, may be negative
   * @return a {@code LocalDate} based on this date with the years added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate plusYears(long yearsToAdd) {
    if (yearsToAdd == 0) {
      return this;
    }
    int newYear = YEAR.checkValidIntValue(year + yearsToAdd);  // safe overflow
    return resolvePreviousValid(newYear, month, day);
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of months added.
   * <p>
   * This method adds the specified amount to the months field in three steps:
   * <ol>
   * <li>Add the input months to the month-of-year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2007-03-31 plus one month would result in the invalid date
   * 2007-04-31. Instead of returning an invalid result, the last valid day
   * of the month, 2007-04-30, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param monthsToAdd the months to add, may be negative
   * @return a {@code LocalDate} based on this date with the months added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate plusMonths(long monthsToAdd) {
    if (monthsToAdd == 0) {
      return this;
    }
    long monthCount = year * 12L + (month - 1);
    long calcMonths = monthCount + monthsToAdd;  // safe overflow
    int newYear = YEAR.checkValidIntValue(Math.floorDiv(calcMonths, 12));
    int newMonth = (int) Math.floorMod(calcMonths, 12) + 1;
    return resolvePreviousValid(newYear, newMonth, day);
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of weeks added.
   * <p>
   * This method adds the specified amount in weeks to the days field incrementing
   * the month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 plus one week would result in 2009-01-07.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param weeksToAdd the weeks to add, may be negative
   * @return a {@code LocalDate} based on this date with the weeks added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate plusWeeks(long weeksToAdd) {
    return plusDays(Math.multiplyExact(weeksToAdd, 7));
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of days added.
   * <p>
   * This method adds the specified amount to the days field incrementing the
   * month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 plus one day would result in 2009-01-01.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param daysToAdd the days to add, may be negative
   * @return a {@code LocalDate} based on this date with the days added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate plusDays(long daysToAdd) {
    if (daysToAdd == 0) {
      return this;
    }
    long mjDay = Math.addExact(toEpochDay(), daysToAdd);
    return LocalDate.ofEpochDay(mjDay);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this date with the specified amount subtracted.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the specified amount subtracted.
   * The amount is typically {@link Period} but may be any other type implementing
   * the {@link TemporalAmount} interface.
   * <p>
   * The calculation is delegated to the amount object by calling
   * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
   * to implement the subtraction in any way it wishes, however it typically
   * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
   * of the amount implementation to determine if it can be successfully subtracted.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToSubtract the amount to subtract, not null
   * @return a {@code LocalDate} based on this date with the subtraction made, not null
   * @throws DateTimeException if the subtraction cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate minus(TemporalAmount amountToSubtract) {
    if (amountToSubtract instanceof Period) {
      Period periodToSubtract = (Period) amountToSubtract;
      return minusMonths(periodToSubtract.toTotalMonths()).minusDays(periodToSubtract.getDays());
    }
    Objects.requireNonNull(amountToSubtract, "amountToSubtract");
    return (LocalDate) amountToSubtract.subtractFrom(this);
  }

  /**
   * Returns a copy of this date with the specified amount subtracted.
   * <p>
   * This returns a {@code LocalDate}, based on this one, with the amount
   * in terms of the unit subtracted. If it is not possible to subtract the amount,
   * because the unit is not supported or for some other reason, an exception is thrown.
   * <p>
   * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
   * See that method for a full description of how addition, and thus subtraction, works.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
   * @param unit the unit of the amount to subtract, not null
   * @return a {@code LocalDate} based on this date with the specified amount subtracted, not null
   * @throws DateTimeException if the subtraction cannot be made
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public LocalDate minus(long amountToSubtract, TemporalUnit unit) {
    return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit)
        : plus(-amountToSubtract, unit));
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of years subtracted.
   * <p>
   * This method subtracts the specified amount from the years field in three steps:
   * <ol>
   * <li>Subtract the input years from the year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2008-02-29 (leap year) minus one year would result in the
   * invalid date 2007-02-29 (standard year). Instead of returning an invalid
   * result, the last valid day of the month, 2007-02-28, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param yearsToSubtract the years to subtract, may be negative
   * @return a {@code LocalDate} based on this date with the years subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate minusYears(long yearsToSubtract) {
    return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1)
        : plusYears(-yearsToSubtract));
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of months subtracted.
   * <p>
   * This method subtracts the specified amount from the months field in three steps:
   * <ol>
   * <li>Subtract the input months from the month-of-year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2007-03-31 minus one month would result in the invalid date
   * 2007-02-31. Instead of returning an invalid result, the last valid day
   * of the month, 2007-02-28, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param monthsToSubtract the months to subtract, may be negative
   * @return a {@code LocalDate} based on this date with the months subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate minusMonths(long monthsToSubtract) {
    return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1)
        : plusMonths(-monthsToSubtract));
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of weeks subtracted.
   * <p>
   * This method subtracts the specified amount in weeks from the days field decrementing
   * the month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2009-01-07 minus one week would result in 2008-12-31.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param weeksToSubtract the weeks to subtract, may be negative
   * @return a {@code LocalDate} based on this date with the weeks subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate minusWeeks(long weeksToSubtract) {
    return (weeksToSubtract == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1)
        : plusWeeks(-weeksToSubtract));
  }

  /**
   * Returns a copy of this {@code LocalDate} with the specified number of days subtracted.
   * <p>
   * This method subtracts the specified amount from the days field decrementing the
   * month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2009-01-01 minus one day would result in 2008-12-31.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param daysToSubtract the days to subtract, may be negative
   * @return a {@code LocalDate} based on this date with the days subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public LocalDate minusDays(long daysToSubtract) {
    return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1)
        : plusDays(-daysToSubtract));
  }

  //-----------------------------------------------------------------------

  /**
   * Queries this date using the specified query.
   * <p>
   * This queries this date using the specified query strategy object.
   * The {@code TemporalQuery} object defines the logic to be used to
   * obtain the result. Read the documentation of the query to understand
   * what the result of this method will be.
   * <p>
   * The result of this method is obtained by invoking the
   * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
   * specified query passing {@code this} as the argument.
   *
   * @param <R> the type of the result
   * @param query the query to invoke, not null
   * @return the query result, null may be returned (defined by the query)
   * @throws DateTimeException if unable to query (defined by the query)
   * @throws ArithmeticException if numeric overflow occurs (defined by the query)
   */
  @SuppressWarnings("unchecked")
  @Override
  public <R> R query(TemporalQuery<R> query) {
    if (query == TemporalQueries.localDate()) {
      return (R) this;
    }
    return ChronoLocalDate.super.query(query);
  }

  /**
   * Adjusts the specified temporal object to have the same date as this object.
   * <p>
   * This returns a temporal object of the same observable type as the input
   * with the date changed to be the same as this.
   * <p>
   * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
   * passing {@link ChronoField#EPOCH_DAY} as the field.
   * <p>
   * In most cases, it is clearer to reverse the calling pattern by using
   * {@link Temporal#with(TemporalAdjuster)}:
   * <pre>
   *   // these two lines are equivalent, but the second approach is recommended
   *   temporal = thisLocalDate.adjustInto(temporal);
   *   temporal = temporal.with(thisLocalDate);
   * </pre>
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param temporal the target object to be adjusted, not null
   * @return the adjusted object, not null
   * @throws DateTimeException if unable to make the adjustment
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override  // override for Javadoc
  public Temporal adjustInto(Temporal temporal) {
    return ChronoLocalDate.super.adjustInto(temporal);
  }

  /**
   * Calculates the amount of time until another date in terms of the specified unit.
   * <p>
   * This calculates the amount of time between two {@code LocalDate}
   * objects in terms of a single {@code TemporalUnit}.
   * The start and end points are {@code this} and the specified date.
   * The result will be negative if the end is before the start.
   * The {@code Temporal} passed to this method is converted to a
   * {@code LocalDate} using {@link #from(TemporalAccessor)}.
   * For example, the amount in days between two dates can be calculated
   * using {@code startDate.until(endDate, DAYS)}.
   * <p>
   * The calculation returns a whole number, representing the number of
   * complete units between the two dates.
   * For example, the amount in months between 2012-06-15 and 2012-08-14
   * will only be one month as it is one day short of two months.
   * <p>
   * There are two equivalent ways of using this method.
   * The first is to invoke this method.
   * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
   * <pre>
   *   // these two lines are equivalent
   *   amount = start.until(end, MONTHS);
   *   amount = MONTHS.between(start, end);
   * </pre>
   * The choice should be made based on which makes the code more readable.
   * <p>
   * The calculation is implemented in this method for {@link ChronoUnit}.
   * The units {@code DAYS}, {@code WEEKS}, {@code MONTHS}, {@code YEARS},
   * {@code DECADES}, {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS}
   * are supported. Other {@code ChronoUnit} values will throw an exception.
   * <p>
   * If the unit is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
   * passing {@code this} as the first argument and the converted input temporal
   * as the second argument.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param endExclusive the end date, exclusive, which is converted to a {@code LocalDate}, not
   * null
   * @param unit the unit to measure the amount in, not null
   * @return the amount of time between this date and the end date
   * @throws DateTimeException if the amount cannot be calculated, or the end temporal cannot be
   * converted to a {@code LocalDate}
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public long until(Temporal endExclusive, TemporalUnit unit) {
    LocalDate end = LocalDate.from(endExclusive);
    if (unit instanceof ChronoUnit) {
      switch ((ChronoUnit) unit) {
        case DAYS:
          return daysUntil(end);
        case WEEKS:
          return daysUntil(end) / 7;
        case MONTHS:
          return monthsUntil(end);
        case YEARS:
          return monthsUntil(end) / 12;
        case DECADES:
          return monthsUntil(end) / 120;
        case CENTURIES:
          return monthsUntil(end) / 1200;
        case MILLENNIA:
          return monthsUntil(end) / 12000;
        case ERAS:
          return end.getLong(ERA) - getLong(ERA);
      }
      throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
    }
    return unit.between(this, end);
  }

  long daysUntil(LocalDate end) {
    return end.toEpochDay() - toEpochDay();  // no overflow
  }

  private long monthsUntil(LocalDate end) {
    long packed1 = getProlepticMonth() * 32L + getDayOfMonth();  // no overflow
    long packed2 = end.getProlepticMonth() * 32L + end.getDayOfMonth();  // no overflow
    return (packed2 - packed1) / 32;
  }

  /**
   * Calculates the period between this date and another date as a {@code Period}.
   * <p>
   * This calculates the period between two dates in terms of years, months and days.
   * The start and end points are {@code this} and the specified date.
   * The result will be negative if the end is before the start.
   * The negative sign will be the same in each of year, month and day.
   * <p>
   * The calculation is performed using the ISO calendar system.
   * If necessary, the input date will be converted to ISO.
   * <p>
   * The start date is included, but the end date is not.
   * The period is calculated by removing complete months, then calculating
   * the remaining number of days, adjusting to ensure that both have the same sign.
   * The number of months is then normalized into years and months based on a 12 month year.
   * A month is considered to be complete if the end day-of-month is greater
   * than or equal to the start day-of-month.
   * For example, from {@code 2010-01-15} to {@code 2011-03-18} is "1 year, 2 months and 3 days".
   * <p>
   * There are two equivalent ways of using this method.
   * The first is to invoke this method.
   * The second is to use {@link Period#between(LocalDate, LocalDate)}:
   * <pre>
   *   // these two lines are equivalent
   *   period = start.until(end);
   *   period = Period.between(start, end);
   * </pre>
   * The choice should be made based on which makes the code more readable.
   *
   * @param endDateExclusive the end date, exclusive, which may be in any chronology, not null
   * @return the period between this date and the end date, not null
   */
  @Override
  public Period until(ChronoLocalDate endDateExclusive) {
    LocalDate end = LocalDate.from(endDateExclusive);
    long totalMonths = end.getProlepticMonth() - this.getProlepticMonth();  // safe
    int days = end.day - this.day;
    if (totalMonths > 0 && days < 0) {
      totalMonths--;
      LocalDate calcDate = this.plusMonths(totalMonths);
      days = (int) (end.toEpochDay() - calcDate.toEpochDay());  // safe
    } else if (totalMonths < 0 && days > 0) {
      totalMonths++;
      days -= end.lengthOfMonth();
    }
    long years = totalMonths / 12;  // safe
    int months = (int) (totalMonths % 12);  // safe
    return Period.of(Math.toIntExact(years), months, days);
  }

  /**
   * Formats this date using the specified formatter.
   * <p>
   * This date will be passed to the formatter to produce a string.
   *
   * @param formatter the formatter to use, not null
   * @return the formatted date string, not null
   * @throws DateTimeException if an error occurs during printing
   */
  @Override  // override for Javadoc and performance
  public String format(DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    return formatter.format(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Combines this date with a time to create a {@code LocalDateTime}.
   * <p>
   * This returns a {@code LocalDateTime} formed from this date at the specified time.
   * All possible combinations of date and time are valid.
   *
   * @param time the time to combine with, not null
   * @return the local date-time formed from this date and the specified time, not null
   */
  @Override
  public LocalDateTime atTime(LocalTime time) {
    return LocalDateTime.of(this, time);
  }

  /**
   * Combines this date with a time to create a {@code LocalDateTime}.
   * <p>
   * This returns a {@code LocalDateTime} formed from this date at the
   * specified hour and minute.
   * The seconds and nanosecond fields will be set to zero.
   * The individual time fields must be within their valid range.
   * All possible combinations of date and time are valid.
   *
   * @param hour the hour-of-day to use, from 0 to 23
   * @param minute the minute-of-hour to use, from 0 to 59
   * @return the local date-time formed from this date and the specified time, not null
   * @throws DateTimeException if the value of any field is out of range
   */
  public LocalDateTime atTime(int hour, int minute) {
    return atTime(LocalTime.of(hour, minute));
  }

  /**
   * Combines this date with a time to create a {@code LocalDateTime}.
   * <p>
   * This returns a {@code LocalDateTime} formed from this date at the
   * specified hour, minute and second.
   * The nanosecond field will be set to zero.
   * The individual time fields must be within their valid range.
   * All possible combinations of date and time are valid.
   *
   * @param hour the hour-of-day to use, from 0 to 23
   * @param minute the minute-of-hour to use, from 0 to 59
   * @param second the second-of-minute to represent, from 0 to 59
   * @return the local date-time formed from this date and the specified time, not null
   * @throws DateTimeException if the value of any field is out of range
   */
  public LocalDateTime atTime(int hour, int minute, int second) {
    return atTime(LocalTime.of(hour, minute, second));
  }

  /**
   * Combines this date with a time to create a {@code LocalDateTime}.
   * <p>
   * This returns a {@code LocalDateTime} formed from this date at the
   * specified hour, minute, second and nanosecond.
   * The individual time fields must be within their valid range.
   * All possible combinations of date and time are valid.
   *
   * @param hour the hour-of-day to use, from 0 to 23
   * @param minute the minute-of-hour to use, from 0 to 59
   * @param second the second-of-minute to represent, from 0 to 59
   * @param nanoOfSecond the nano-of-second to represent, from 0 to 999,999,999
   * @return the local date-time formed from this date and the specified time, not null
   * @throws DateTimeException if the value of any field is out of range
   */
  public LocalDateTime atTime(int hour, int minute, int second, int nanoOfSecond) {
    return atTime(LocalTime.of(hour, minute, second, nanoOfSecond));
  }

  /**
   * Combines this date with an offset time to create an {@code OffsetDateTime}.
   * <p>
   * This returns an {@code OffsetDateTime} formed from this date at the specified time.
   * All possible combinations of date and time are valid.
   *
   * @param time the time to combine with, not null
   * @return the offset date-time formed from this date and the specified time, not null
   */
  public OffsetDateTime atTime(OffsetTime time) {
    return OffsetDateTime.of(LocalDateTime.of(this, time.toLocalTime()), time.getOffset());
  }

  /**
   * Combines this date with the time of midnight to create a {@code LocalDateTime}
   * at the start of this date.
   * <p>
   * This returns a {@code LocalDateTime} formed from this date at the time of
   * midnight, 00:00, at the start of this date.
   *
   * @return the local date-time of midnight at the start of this date, not null
   */
  public LocalDateTime atStartOfDay() {
    return LocalDateTime.of(this, LocalTime.MIDNIGHT);
  }

  /**
   * Returns a zoned date-time from this date at the earliest valid time according
   * to the rules in the time-zone.
   * <p>
   * Time-zone rules, such as daylight savings, mean that not every local date-time
   * is valid for the specified zone, thus the local date-time may not be midnight.
   * <p>
   * In most cases, there is only one valid offset for a local date-time.
   * In the case of an overlap, there are two valid offsets, and the earlier one is used,
   * corresponding to the first occurrence of midnight on the date.
   * In the case of a gap, the zoned date-time will represent the instant just after the gap.
   * <p>
   * If the zone ID is a {@link ZoneOffset}, then the result always has a time of midnight.
   * <p>
   * To convert to a specific time in a given time-zone call {@link #atTime(LocalTime)}
   * followed by {@link LocalDateTime#atZone(ZoneId)}.
   *
   * @param zone the zone ID to use, not null
   * @return the zoned date-time formed from this date and the earliest valid time for the zone, not
   * null
   */
  public ZonedDateTime atStartOfDay(ZoneId zone) {
    Objects.requireNonNull(zone, "zone");
    // need to handle case where there is a gap from 11:30 to 00:30
    // standard ZDT factory would result in 01:00 rather than 00:30
    LocalDateTime ldt = atTime(LocalTime.MIDNIGHT);
    if (zone instanceof ZoneOffset == false) {
      ZoneRules rules = zone.getRules();
      ZoneOffsetTransition trans = rules.getTransition(ldt);
      if (trans != null && trans.isGap()) {
        ldt = trans.getDateTimeAfter();
      }
    }
    return ZonedDateTime.of(ldt, zone);
  }

  //-----------------------------------------------------------------------
  @Override
  public long toEpochDay() {
    long y = year;
    long m = month;
    long total = 0;
    total += 365 * y;
    if (y >= 0) {
      total += (y + 3) / 4 - (y + 99) / 100 + (y + 399) / 400;
    } else {
      total -= y / -4 - y / -100 + y / -400;
    }
    total += ((367 * m - 362) / 12);
    total += day - 1;
    if (m > 2) {
      total--;
      if (isLeapYear() == false) {
        total--;
      }
    }
    return total - DAYS_0000_TO_1970;
  }

  //-----------------------------------------------------------------------

  /**
   * Compares this date to another date.
   * <p>
   * The comparison is primarily based on the date, from earliest to latest.
   * It is "consistent with equals", as defined by {@link Comparable}.
   * <p>
   * If all the dates being compared are instances of {@code LocalDate},
   * then the comparison will be entirely based on the date.
   * If some dates being compared are in different chronologies, then the
   * chronology is also considered, see {@link java.time.chrono.ChronoLocalDate#compareTo}.
   *
   * @param other the other date to compare to, not null
   * @return the comparator value, negative if less, positive if greater
   */
  @Override  // override for Javadoc and performance
  public int compareTo(ChronoLocalDate other) {
    if (other instanceof LocalDate) {
      return compareTo0((LocalDate) other);
    }
    return ChronoLocalDate.super.compareTo(other);
  }

  int compareTo0(LocalDate otherDate) {
    int cmp = (year - otherDate.year);
    if (cmp == 0) {
      cmp = (month - otherDate.month);
      if (cmp == 0) {
        cmp = (day - otherDate.day);
      }
    }
    return cmp;
  }

  /**
   * Checks if this date is after the specified date.
   * <p>
   * This checks to see if this date represents a point on the
   * local time-line after the other date.
   * <pre>
   *   LocalDate a = LocalDate.of(2012, 6, 30);
   *   LocalDate b = LocalDate.of(2012, 7, 1);
   *   a.isAfter(b) == false
   *   a.isAfter(a) == false
   *   b.isAfter(a) == true
   * </pre>
   * <p>
   * This method only considers the position of the two dates on the local time-line.
   * It does not take into account the chronology, or calendar system.
   * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
   * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
   *
   * @param other the other date to compare to, not null
   * @return true if this date is after the specified date
   */
  @Override  // override for Javadoc and performance
  public boolean isAfter(ChronoLocalDate other) {
    if (other instanceof LocalDate) {
      return compareTo0((LocalDate) other) > 0;
    }
    return ChronoLocalDate.super.isAfter(other);
  }

  /**
   * Checks if this date is before the specified date.
   * <p>
   * This checks to see if this date represents a point on the
   * local time-line before the other date.
   * <pre>
   *   LocalDate a = LocalDate.of(2012, 6, 30);
   *   LocalDate b = LocalDate.of(2012, 7, 1);
   *   a.isBefore(b) == true
   *   a.isBefore(a) == false
   *   b.isBefore(a) == false
   * </pre>
   * <p>
   * This method only considers the position of the two dates on the local time-line.
   * It does not take into account the chronology, or calendar system.
   * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
   * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
   *
   * @param other the other date to compare to, not null
   * @return true if this date is before the specified date
   */
  @Override  // override for Javadoc and performance
  public boolean isBefore(ChronoLocalDate other) {
    if (other instanceof LocalDate) {
      return compareTo0((LocalDate) other) < 0;
    }
    return ChronoLocalDate.super.isBefore(other);
  }

  /**
   * Checks if this date is equal to the specified date.
   * <p>
   * This checks to see if this date represents the same point on the
   * local time-line as the other date.
   * <pre>
   *   LocalDate a = LocalDate.of(2012, 6, 30);
   *   LocalDate b = LocalDate.of(2012, 7, 1);
   *   a.isEqual(b) == false
   *   a.isEqual(a) == true
   *   b.isEqual(a) == false
   * </pre>
   * <p>
   * This method only considers the position of the two dates on the local time-line.
   * It does not take into account the chronology, or calendar system.
   * This is different from the comparison in {@link #compareTo(ChronoLocalDate)}
   * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
   *
   * @param other the other date to compare to, not null
   * @return true if this date is equal to the specified date
   */
  @Override  // override for Javadoc and performance
  public boolean isEqual(ChronoLocalDate other) {
    if (other instanceof LocalDate) {
      return compareTo0((LocalDate) other) == 0;
    }
    return ChronoLocalDate.super.isEqual(other);
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if this date is equal to another date.
   * <p>
   * Compares this {@code LocalDate} with another ensuring that the date is the same.
   * <p>
   * Only objects of type {@code LocalDate} are compared, other types return false.
   * To compare the dates of two {@code TemporalAccessor} instances, including dates
   * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
   *
   * @param obj the object to check, null returns false
   * @return true if this is equal to the other date
   */
  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj instanceof LocalDate) {
      return compareTo0((LocalDate) obj) == 0;
    }
    return false;
  }

  /**
   * A hash code for this date.
   *
   * @return a suitable hash code
   */
  @Override
  public int hashCode() {
    int yearValue = year;
    int monthValue = month;
    int dayValue = day;
    return (yearValue & 0xFFFFF800) ^ ((yearValue << 11) + (monthValue << 6) + (dayValue));
  }

  //-----------------------------------------------------------------------

  /**
   * Outputs this date as a {@code String}, such as {@code 2007-12-03}.
   * <p>
   * The output will be in the ISO-8601 format {@code uuuu-MM-dd}.
   *
   * @return a string representation of this date, not null
   */
  @Override
  public String toString() {
    int yearValue = year;
    int monthValue = month;
    int dayValue = day;
    int absYear = Math.abs(yearValue);
    StringBuilder buf = new StringBuilder(10);
    if (absYear < 1000) {
      if (yearValue < 0) {
        buf.append(yearValue - 10000).deleteCharAt(1);
      } else {
        buf.append(yearValue + 10000).deleteCharAt(0);
      }
    } else {
      if (yearValue > 9999) {
        buf.append('+');
      }
      buf.append(yearValue);
    }
    return buf.append(monthValue < 10 ? "-0" : "-")
        .append(monthValue)
        .append(dayValue < 10 ? "-0" : "-")
        .append(dayValue)
        .toString();
  }

  //-----------------------------------------------------------------------

  /**
   * Writes the object using a
   * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
   *
   * @return the instance of {@code Ser}, not null
   * @serialData <pre>
   *  out.writeByte(3);  // identifies a LocalDate
   *  out.writeInt(year);
   *  out.writeByte(month);
   *  out.writeByte(day);
   * </pre>
   */
  private Object writeReplace() {
    return new Ser(Ser.LOCAL_DATE_TYPE, this);
  }

  /**
   * Defend against malicious streams.
   *
   * @param s the stream to read
   * @throws InvalidObjectException always
   */
  private void readObject(ObjectInputStream s) throws InvalidObjectException {
    throw new InvalidObjectException("Deserialization via serialization delegate");
  }

  void writeExternal(DataOutput out) throws IOException {
    out.writeInt(year);
    out.writeByte(month);
    out.writeByte(day);
  }

  static LocalDate readExternal(DataInput in) throws IOException {
    int year = in.readInt();
    int month = in.readByte();
    int dayOfMonth = in.readByte();
    return LocalDate.of(year, month, dayOfMonth);
  }

}
